1. Field of the Invention
The present invention relates to an apparatus for recognizing an image, and more particularly to an apparatus for recognizing an image, capable of recognizing an image pattern from a human being with high accuracy.
2. Description of the Related Art
An amorphous-silicon thin film transistor liquid crystal display apparatus (a-Si TFT-LCD apparatus), which is a kind of flat panel display, is widely applied to an electronic instrument, for example, such as a notebook computer, a monitor, a television set, a mobile communication system, a hand-held electronic appliance and so on.
Also, since the a-Si TFT-LCD, generally, includes a photosensitive material that is chemically changeable in response to a light, the a-Si TFT-LCD may be broadly used to biometrics industries as a photoelectric sensor.
The biometrics industries relate to a personal verification system using inherent biological properties, for example, such as a fingerprint, a voice, a facial feature, a hand or an eye iris. In view of cost, convenience and accuracy, a personal verification system using the fingerprint among the inherent biological properties is widely used.
A conventional fingerprint recognition apparatus includes a photoelectric sensor, for example, such as a sensing TFT, a switching TFT, a storage capacitor, or the like.
An operation mechanism for carrying out recognition of the fingerprint recognition apparatus using the photoelectric sensor is as follows.
The sensing TFT receives a light emitted from a light source and reflected corresponding to a fingerprint image printed on a human finger. When the sensing TFT is turned on in response to the light, the storage capacitor charges an electron charge in proportion to an amount of the light received into the sensing TFT. The amount of the light received into the sensing TFT may be different according to a position from which the light is reflected because a reflectance between a light reflected from a ridge portion that is protruded portion of the human finger and a light reflected from a valley portion that is recessed portion of the human finger is different from each other. Thus, the amount of the electron charge charged into the sensing TFT may be varied due to the amount of the reflected light from the fingerprint image.
The switching TFT reads out the amount of the electron charge charged into the storage capacitor and outputs a signal corresponding to the amount of the electron charge through a sensing signal output line to an external.
As described above, the conventional fingerprint recognition apparatus may recognize the fingerprint image based on the reflected light from the fingerprint image of the human finger while the human finger does not directly make contact with the fingerprint recognition apparatus. Also, even if an object having the fingerprint image is not the human finger, the conventional fingerprint recognition apparatus recognizes the fingerprint image as a biological signal, for example, such as the fingerprint of the human finger, when the object makes contact with the fingerprint recognition apparatus.
That is, although the fingerprint image printed on an object, for example, such as a paper or the like, makes contact with the fingerprint recognition apparatus, the fingerprint recognition apparatus recognizes the fingerprint image printed on the object as a normal biological signal from the human finger. As a result, an accuracy of the fingerprint recognition apparatus for verifying a normal user may be lowered.